Portopulmonary hypertension (POPH), or pulmonary arterial hypertension associated with cirrhosis, carries a high mortality and often precludes liver transplantation. Many POPH patients have preserved or increased cardiac output; therefore, decreasing pulmonary artery pressure rather than improving cardiac output is more important in reducing liver transplant risk, and this makes sildenafil an attractive therapeutic option. We assessed the clinical response of patients with POPH treated with sildenafil monotherapy. We retrospectively reviewed the charts of 10 patients with POPH and sildenafil monotherapy. Eight of 10 patients had hepatitis C virus infection. Patients took 31 ± 14 mg (mean ± standard deviation) thrice daily and were followed for 21 ± 16 months. The World Health Organization functional class improved from 3.0 ± 0.0 to 2.3 ± 0.5 at 1 year (P < 0.05). Four of 8 patients increased the 6‐minute walk distance at 1 year by 30 m or more. Three patients became transplant‐eligible, 1 of whom underwent successful transplantation, and 3 patients have been stable without progression of liver disease or POPH. The remainder were not transplant candidates because of refractory POPH (n = 2) or other comorbidities (n = 2). We conclude that sildenafil may be an effective therapy for POPH that can stabilize or improve hemodynamics in patients with POPH and thereby facilitate liver transplantation. Liver Transpl 15:15–19, 2009. © 2008 AASLD.